Method of making wrenches



April 5, 1938. I F. HAIST 2,112,840

' METHOD OF MAKING WRENCHES Filed May 8, 1935 Patented Apr. 5, 1938UNITED ST TES PATENT OFFICE assignments, to J. H. W

illiams & 00., Butfalo, N. Y., a corporation of New York Application'May 8, 1935, Serial No. 20,425

4 Claims.

solutions thereof are disclosed in detail in they herein patentspecification, wherein,--

-In the accompanying figures:

Fig. 1 is a fragmentary side elevation of my improved wrench.

Fig. 2 is a vertical, longitudinal section thereof, taken on line 2--2,Fig. 4.

Figs. 3 and 4 are fragmentary, horizontal sections through said wrench,taken on correspondingly numbered lines of Fig. 2.

Similar characters of reference indicate like parts in the severalfigures of the drawing.

The present invention has been illustrated as applied to a solid, forgedsteel, adjustable end wrench of the oblique handle type. The invention,however, is not confined to this particular type of wrench, but may beutilized in any adjustable wrench although most efiectively in anadjustable end wrench in which the head, fixed jaw and handle are formedfrom one piece of metal.

The wrench here illustrated consists primarily of a single steel forgingconstituting a head H), a fixed jaw I I and an oblique handle I 2, andhaving a movable jaw l3 slidably mounted in said head Ill. The medialportion of said head In at a point rearwardly of the fixed jaw II is cutaway to form the relatively narrow, longitudinal, vertical, fiat-facedalignment throat l4. Said throat is relatively narrow in a horizontal,transverse direction and opens at its rear end into a vertical guidewayl5 which is relatively wide in a horizontal, transverse direction. Therear or inner portion l6 of said vertical guide I5 is semicylindrical incross section (as seen in Figs. 3.

and 4), while its front or outer portion is rectangular in cross sectionforming a pair of vertical, longitudinal, fiat side walls I1, I! and apair of vertical, transverse, fiat abutments l8, l8.

The movable jaw l3 of the wrench is integrally connected on its rearface with a vertical, longitudinal shank 20 which is relatively'narrowina transverse direction and is rectangular in hori- Y zontal section (seeFigs. 3 and 4) and is slidably received within the relatively narrow,fiat-faced, alignment throat M. This shank 20 maintains the movable jawl3 in transverse alignment at whatever slidable position it may happento 00- cupy, i. c. said shank 20 in cooperation with said alignmentthroat I4 keeps the movable jaw l3 at all times in correct verticalregister with the fixed jaw ll. Secured integrally to the rear end ofsaid fiat-faced alignment throat I4 is a vertical slide 2|. The latterhas the same horizontal cross sectional shape as the vertical guidewayl5, being of semi-cylindrical, horizontal cross section at its rear partand of rectangular, horizontal cross section at its front part. Saidvertical slide 2i of the movable jaw l3 extends some distance both aboveand below said movable jaw I 3 for reasons which are well known in theart.

The rear, vertical, semi-cylindrical face of said slide 2| is hobbed orotherwise suitably machined to form a vertical rack 22. The head H! ofthe wrench is suitably cut away to form the rectangular opening 23 whichextends horizontally clear through said head l0. Arranged in saidopening 23 is an operating worm gear 24, the spiral gear tooth of whichengages the teeth of the rack 22 so that when said worm gear 24 isrotated in the one or other direction, the movable jaw I 3 is movedtoward or away from the fixed jaw II as may be desired for adjusting thewrenchto any particular size of nut. The periphery of said worm gear ispreferably knurled in the usual manner, as shown, to facilitate theturning of said worm gear manually.

Said worm gear 24 is rotatably mounted on a pin 25 the extreme lower endof which is enlarged and male threaded at 26 while the shank or rest ofthe pin is of cylindrical shape and is smaller in diameter than thethreaded portion 26. The extreme upper portion 21 of the cylindricalshank of said pin is received'within an upper vertical hole 28 situatedjust above the I rectangular opening 23, while the lower portion 2H ofthe cylindrical shank of said pin is re- 1 ceived within a lower,vertical hole 28! in axial. alignment with aforesaid hole 28 andsituated just below said rectangular opening 23. Said lower verticalhole 28! is employed to guide the tap when tapping the female threadwhich receives the male thread 26 of the pin 25. By this constructionsaid pin 25 is solidly supported by its upper and lower'cylindricalportions 21, 2' just above and below said rectangular opening 23 thusrequiring of the-thread 26 only the duty of pushing the pin 25 upvertically into place and firmly holding it in this position. This pointto be manufactured from straight bar stock with no cutting operationother than the screw driver slot 3..

It is desirable to have the fixed and movable jaws ll and l3,respectively, as far apart as possible for any given setting of the wormgear 24 and its companion rack 22, so as to take up whatever slack maybe present. One point where this slack occurs (when the permittedmanufacturing tolerances are very large) is in the vertical movement ofthe operating worm gear 24 in its rectangular opening 23. This slack istaken up in an improved manner in the present invention by a conicalcompression spring II the upper, large end of which bears upwardlyagainst the upper flat face of the opening 23 while its lower, small endis received within and bears resiliently downwardly against the smallend of a conical counterbore 32 formed axially in the upper end of theoperating worm gear 24. Such a conical counterbore is much lessexpensive to obtain in large quantity production than the conventionalrectangular counterbore and also has the advantage of permitting the useof a relatively long compression spring 3i without mechanicallyweakening the worm gear 24. This conical arrangement has the furtheradvantageof imposing a greater than usual frictional resistance toturning of the worm gear 24 because of the fact that the fric-- tlonalpressure which is normal to the face of the conical counterbore 32 (andhence is in opposition to the rotation of the worm gear 24) is greaterthan the vertical thrust of the conical spring 3| The method ofmanufacture The first operation is the forging of the fixed jaw, wrenchhead I. and handle l2 from one piece of properly alloyed high carbonsteel. In this forging process the rectangular opening 23 is alsoformed. The wrench is then drilled, as shown in Fig. 3 by the dottedline 33 together with the full line It, the latter forming ultimatelythe rear or inner end of the guideway l5 of the wrench head ll. Saidguideway i5 is then broached with a suitable broacha It is to beparticularly noted that, in this, broaching operation, the broach cutsonly at the front or outer part of said guideway l5 andisiirmlybraced,while doingthis cutting, by the already formed semi-cylindrical surfaceIt. This broaching results in the formation of the flat side walls ll,I1 and the flat abutments ll, It. The alignment throat I4 is then formedin the usual and well known manner.

The holes 28 and 2" are now drilled, and the latter then used as a guidefor tapping the female thread which engages the male thread 26 of thepin '25. The movable jaw l3 with its integral shank 20 and slide 2 l isthen slid into place. The

r'nale thread 26 of the pin 28 is then formed by rolling or otherwiseand assembled withits companion operating worm gear 24 and conicalcompression spring Ii.

l'ormaximmnstrengthawrenchofthistype should be rotated in the directionshown by the full line'arrows of Fig. 2. It'must be borne in mind,however, that the wrench will frequently be usedinsuchadirectionastocause thrusts onthe jaws of the type shown .by dotted linearrows. In

, either case it will be noted that the force, to which vention, by thepressing of the flat, vertical, transverse faces of the slide 2| againstthe flat, vertical. transverse abutments l8, ll. These flat faces andabutments are disposed perpendicularly of the.

. imposed pressure and consequently cannot spread the side walls of theguideway I, as occurs in wrenches of conventional construction, wheneverthe wrench is subjected to heavy abuse or overloading beyond the elasticlimit of the metal. As

a result. this improved form of wrench maintains its original strengthand smoothness of operation even if subjected to much abuse oroverloading, provided, of course, that the load isnot sumcient- 1yexcessive to strain the metal beyond its ultimate strength.

In this connection it is to be noted that even for loads within theelastic limit of the metal, this improved wrench is superior to theconventional wrench in that the slide 2| of the movable jaw i3 isprevented from binding in its guideway i5 because of the fact that anylateral pressure exerted in any lateral direction by said slide isimposed .upon a surface which is perpendicular of said force, whereas ina number of conventional wrenches of this general type longitudinalpressures in a forward or outward direction are imposed upon a surfacewhich is oblique to said pressure, similar to the manner in which a Vpower transmission belt exerts more pressure than a flat belt.

When an operator is using a wrench of this character, he usually movesthe movable jaw I! to a certain position and then successively appliesthe wrench to the nut, gives the same a partial turn, removes the wrenchand returns to its original position and gives said nut another partialturn. In this procedure it is important that the operating worm gear 24be not moved out of its properly adjusted position. This is effected, inthe present invention, by providing a more than usual frictionalresistance to the turning of said worm gear by the provision of theconical compression spring 3| in the conical counterbore 32, in thiscase deliberately obtaining the very V belt type of friction which inthe case of the slide 2i was seen to be objectionable. This conicalconstruction also permits of a long spring to give a soft resilient,frictional action and to take up the slack ofthe womb-gear 24 relativelyto the wrench head III, and accomplishing these results withoutmechanically weakening said worm gear 24, as would occur if acounterbore of equivalently large diameter were to extend an equivalentdistance cylindricallly into the upper face of said worm gear. 4

In addition to the foregoing, said worm wheel 24 always moves freely onits pin 25 by reason of the fact that any lateral forces to which saidworm gear or pin may be subjected are not imposed upon the thread 25 butonly upon the cylindrical 2,112,840 j 3 surfaces of the holes 28, 28 lwhich may be accurately drilled (and even reamed if desired) atrelatively little expense. Because of this fact said pin does not becomeloosened when the wrench is being used, and hence said pin 25 does notbecome loosened and finally fallout as frequently occurs when thewrenches are subjected to constant vibration, as when being carried inthe tool box of an automobile.

I claim as my invention:

1. The method of making a wrench consisting of the forming of a headhaving a fixed jaw; drilling a hole' in said head perpendicularly ofsaid' fixed jaw; passing a broach into said drilled hole and cutting afiat abutment on only the front side of said hole; guiding andsupporting the rear side of said broach during the broaching operationon therear cylindrical surface of the drilled hole; assembling a movablejaw having a guide which is received within said broached hole' and hasa semi-cylindrical rear portion and a flat-faced front portion; andproviding means for moving said movable jaw relatively to said head, ina direction parallel to said broached hole.

2. The method of making a wrench consisting of the forming of a 'headhaving a fixed jaw; drilling a hole in said head perpendicularly of saidfixed jaw; passing a broach into said drilled I hole and cutting a pairof flat abutments on only the front side of said hole; guiding andsupporting the rear side of said broach during the broaching operationon the rear cylindrical surface of the drilled hole; assembling amovable jaw havinga guide which is received within said broached holeand has a semi-cylindrical rear portion and a dual shouldered frontportion; and providing means for moving said movable .jaw, relatively tosaid head, in a. direction parallel to said broached hole.

3. The method of making a wrench consisting of the forming of a headhaving a fixed jaw; drilling a hole in said head perpendicularly of saidfixed jaw; passing a broachinto said drilled hole and cutting a fiatabutment at a-point located rearwardly of its extreme front portion;-

guiding and supporting the rear side of said broach during the broachingoperation on the rear cylindrical surface of the drilled hole;assembling a movable jaw having a guide which is received within saidbroached hole and has a semi-cylindrical rear portion and'a flat facedfront portion; and providing .means for moving said movable jaw,relatively to said head, in a direction-parallel to said broached hole.

4. The method of making a wrench consisting of the forming of a headhaving a fixed jaw; drilling a hole in saidhead perpendicularly of saidfixed jaw; passing a broach into said drilled hole and cutting a pairof'symmetrical flat abutments each at a point located rearwardly of its.

extreme front portion; guiding and supporting the rear side of saidbroach during the broaching operation on the rear cylindrical surface ofthe drilled hole; assembling a movable jaw having a guide which isreceived within said broached hole and has a semi-cylindrical rearportion and a symmetrical dual-shouldered front portion; and providingmeans for moving saidmovable jaw relatively to said head, in a directionparallelto said broached hole.

FOSTER A. HAIST.

